OMVPE regrowth of CH3I-vapor-etched GaAs

Abstract

In experiments on the interrupted growth of GaAs by organometallic vapor phase epitaxy (OMVPE), we have compared the properties of two types of epilayers: those grown on CH3I-vapor-etched first epilayers and those grown on first epilayers that were either untreated or etched with H2SO4. The OMVPE growth and CH3I etching were performed in two different reactors, and each sample was briefly exposed to air immediately before being placed in the OMVPE reactor for growth of the second epilayer. For CH3I etch temperatures below 500° C, the two types of second epilayers are comparable in surface morphology, as characterized by Nomarski interference microscopy, and in optical quality, as characterized by low-temperature photoluminescence measurements. Electrical characterization by C-V depth profiling shows that electron accumulation at the regrowth interface is increased very little by CH3I etching. Such etching prior to regrowth eliminates most of the electron accumulation resulting from H2SO4 etching of the first epilayer.